Wednesday, December 6, 2023

China battles deadly AI strain

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By Barbara Olejnik

Poultry Times Staff

GAINESVILLE, Ga. — China is continuing to battle its fifth and largest wave of the H7N9 strain of avian influenza, which has killed 100 people since October 2016, when latest outbreak began.

Since the beginning of this latest outbreak, China has reported at least human 425 cases of the virus — 67 of them in the Feb. 12-18 period.

Most of the cases are concentrated at live poultry markets, not at chicken farms, in the south and on the eastern seaboard.

The main reasons for this concentration are the weather conditions and the preference of Chinese people to buy live or freshly slaughtered chickens.

Because the H7N9 virus has been found in poultry markets, China’s Prime Minister Li Keqiang has asked provincial officials to close poultry markets as soon as infected birds of found, according to a report from the University of Minnesota’s Center for Infectious Disease Research & Policy.

The United Nations Food & Agriculture Organization (FAO) has also reported that more provinces and cities are closing poultry markets and cubing live-poultry transport.

In Jiangxi province, Chinese officials ordered all live-bird markets and trading locations in Nanchang city closed for 14 days and Guangdong province also recently suspended all live-bird transport from high-risk provinces such as Anhui, Jinangxi and Zhejiang.

In addition to closing the markets, China is training health workers in the screening, early diagnosis and treatment of the disease, while urging people to avoid contact with live birds.

In Hong Kong, the region’s Centre for Health Protection’s Port Health Office conducts health surveillance measures at all boundary control points. Thermal imaging systems are in place for body temperature checks on inbound travelers from mainland China as well as other parts of the world. Suspected cases will be immediately referred to public hospitals for follow-up.

However, some health experts have said that efforts to halt the spread of the disease has come too late — that preventive steps should have been taken long before the flu season started.

Authorities should have stepped up their surveillance going into the peak season, the experts said, noting that authorities had lowered their guard after the last two years when outbreaks were not so severe.

“Work should be done even before the first human case is found each year,” said Professor Malik Peiris, a public health virologist at the University of Hong Kong, in a South China Morning Post report.

The H7N9 strain is not believed to be transmitted between humans, but rather by infected poultry. Experts have said the Chinese habit of buying live or freshly slaughtered chickens has contributed to the continuing virus.

Temporarily closing of poultry markets will not solve the problem, the experts state.

The way out of the cycle of outbreaks is to change the Chinese poultry industry by shifting to large-scale poultry farming and slaughtering.

Until now, H7N9 has shown little or no clinical symptoms in birds, despite being highly pathogenic in humans. However, China has reported detecting an evolution in the virus that is capable of causing severe disease in poultry.

This could mean the disease will become more apparent if birds begin to die, thereby allowing for earlier detection of the virus and better control.

The World Health Organization notes that since the virus continues to be detected in animals and environments, further human cases can be expected.

However, the WHO also stated that “current epidemiological and virological evidence suggests that this virus has not acquired the ability of sustained transmission among humans. Based on available information we have, further community level spread is considered unlikely.”

The WHO added, Human infections with the H7N9 virus are unusual and because there is the potential for significant public health impact, it needs to be monitored closely.

European outbreaks

The H5N8 strain of avian influenza continues to afflict numerous European countries with Spain reporting its first H5N8 outbreak in poultry, following two earlier detections in wild birds.

The outbreak in Spain began on Feb. 18 at a farm in Catalonia with the deaths of ducks in one of the facility’s six sheds.

The virus killed 723 of 17,800 birds on the farm and the rest were destroyed as a control measure, according to a CIDRAP report.

At least seven other European countries have reported outbreaks of the H5N8 strain occurring in mid- to late-February. These include:

France — Reported 68 new outbreaks in poultry and 13 more detections in wild birds.  The latest farm outbreaks in southwestern France had start dates ranging from Feb. 1 to Feb. 20 and the facilities housed 33,568 susceptible birds. France plans to cull 600,000 ducks as part of efforts to prevent a spread of the virus.

Hungary — Nineteen more outbreaks in poultry, 13 at farms and six involving backyard birds. The virus killed 455,528 susceptible birds and the rest were destroyed.

Bulgaria — one more outbreak in backyard poultry killing 25 of 62 birds.

Croatia — Three mute swans found dead on Feb. 14 in Sisak-Moslavian County.

Italy — Two more outbreaks, one at a turkey farm housing nearly 20,000 birds in Lombardy region and the other in a wild duck found sick in a nature park in the north.

Slovakia — One more detection, involving a greylag goose found dead on Feb. 21 in a lake in Bratislavia region.

United Kingdom — An outbreak at a small farm housing 35 chickens near the town of Haltwhistle in Northumberland.

Poland — Nine outbreaks affecting 15 wild birds, most of them swans, found dead between Feb.12 and Feb. 20 across six provinces.

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